Fix #13706 fuzzing crash (assert) in TemplateSimplifier::TokenAndName::TokenAndName() (danmar#8102)

Co-authored-by: chrchr-github <noreply@github.com>

Author: chrchr-github

lib/templatesimplifier.cpp

@@ -219,9 +219,8 @@ TemplateSimplifier::TokenAndName::TokenAndName(Token *token, std::string scope,
     }
 
     // make sure at most only one family flag is set
-    assert(isClass() ? !(isFunction() || isVariable()) : true);
-    assert(isFunction() ? !(isClass() || isVariable()) : true);
-    assert(isVariable() ? !(isClass() || isFunction()) : true);
+    if (isClass() + isFunction() + isVariable() > 1)
+        syntaxError(token);
 
     if (mToken)
         mToken->templateSimplifierPointer(this);

test/cli/fuzz-crash/crash-5ac13e244448ff767f6596c220edb9ef7b61fa6d

@@ -0,0 +1 @@
+template<>struct t<>();